on the roofs of buildings. But why go to all that trouble when cities are full of black surfaces already。
经典精讲上课后练习Tag内容描述：
1、2019-2020年高考英语二轮复习 阅读理解专题 经典精讲（上）课后练习题一：Sometimes，the simplest ideas are the best. For example，to absorb heat from the sun to heat water, you need large, flat, black surfaces. One way to do that is to build those surfaces specially, on the roofs of buildings. But why go to all that trouble when cities are full of black surfaces already, in the form of asphalt (柏油) roads?Ten years ago, this thought came into the mind of Arian de Bondt, a Dutch engineer. He finally。